From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B1C8F2054EF; Thu, 12 Dec 2024 16:56:22 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1734022582; cv=none; b=O4imTjqKQA8pI+MAWbJ/s5TOvRvqNyi/8G7dP8H9YGOPmo+TvrO+p1KxyMXVtA4y09MGcPd4GHBxaIJEFrTV7WIjV/2g7NS821qHr6I5R5a+JsSnzU1M9zdnxgr1Z3Rzn+re8iMzies0MG1N4Wyoa3FfD9u12CGtbgBuHiFD7ic= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1734022582; c=relaxed/simple; bh=R7WxliadeRyRq+jM6h+QR6AsLCMyHbMr8WBn2LvWvSQ=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=ZISO6DEAjUlPisvDBCkZiHKQe7+hAoLEde6OhAxsruvwVh/SFmRfi0XsGfZ5glDHeGH/owi+6l8Ywv3odgYP1209eF+D8Og7H22A7YNPgM434dKYQZoko829XtYrziFrHU3MR5EJxWTyxw78kFj/B/AsoH/AYKZhgMm6fvhcd00= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=jtmX+ec9; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="jtmX+ec9" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1EAC1C4CECE; Thu, 12 Dec 2024 16:56:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1734022582; bh=R7WxliadeRyRq+jM6h+QR6AsLCMyHbMr8WBn2LvWvSQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=jtmX+ec9FbqBL/d/SLMI0BJGP9U8a+TfNs1tfnHB+PMci5vyAyz0HTRLobhoYnq4d SBNtI1kjrdCRE+lkUFf1a7OoJb1aRlAWP/fzqcQwNwLEalDPrDCCI8e/Bkc3TfSX1g 6EN+xlHf1zFQNpmDad4WP8W0usmauuKkgfWueJQs= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Maxime Chevallier , Paolo Abeni , Sasha Levin Subject: [PATCH 5.15 280/565] net: stmmac: dwmac-socfpga: Set RX watchdog interrupt as broken Date: Thu, 12 Dec 2024 15:57:55 +0100 Message-ID: <20241212144322.521241361@linuxfoundation.org> X-Mailer: git-send-email 2.47.1 In-Reply-To: <20241212144311.432886635@linuxfoundation.org> References: <20241212144311.432886635@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Maxime Chevallier [ Upstream commit 407618d66dba55e7db1278872e8be106808bbe91 ] On DWMAC3 and later, there's a RX Watchdog interrupt that's used for interrupt coalescing. It's known to be buggy on some platforms, and dwmac-socfpga appears to be one of them. Changing the interrupt coalescing from ethtool doesn't appear to have any effect here. Without disabling RIWT (Received Interrupt Watchdog Timer, I believe...), we observe latencies while receiving traffic that amount to around ~0.4ms. This was discovered with NTP but can be easily reproduced with a simple ping. Without this patch : 64 bytes from 192.168.5.2: icmp_seq=1 ttl=64 time=0.657 ms With this patch : 64 bytes from 192.168.5.2: icmp_seq=1 ttl=64 time=0.254 ms Fixes: 801d233b7302 ("net: stmmac: Add SOCFPGA glue driver") Signed-off-by: Maxime Chevallier Link: https://patch.msgid.link/20241122141256.764578-1-maxime.chevallier@bootlin.com Signed-off-by: Paolo Abeni Signed-off-by: Sasha Levin --- drivers/net/ethernet/stmicro/stmmac/dwmac-socfpga.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-socfpga.c b/drivers/net/ethernet/stmicro/stmmac/dwmac-socfpga.c index 6b447d8f0bd8a..9c726fe40acdf 100644 --- a/drivers/net/ethernet/stmicro/stmmac/dwmac-socfpga.c +++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-socfpga.c @@ -426,6 +426,8 @@ static int socfpga_dwmac_probe(struct platform_device *pdev) plat_dat->bsp_priv = dwmac; plat_dat->fix_mac_speed = socfpga_dwmac_fix_mac_speed; + plat_dat->riwt_off = 1; + ret = stmmac_dvr_probe(&pdev->dev, plat_dat, &stmmac_res); if (ret) goto err_remove_config_dt; -- 2.43.0